NPS Pharma will have to wait another three months for an FDA OK

NPS CEO Francois Nader

The FDA has postponed its final decision on an orphan drug from NPS Pharma ($NPSP), taking its time with the company's application and delaying the fate of a closely watched therapy.

The agency has extended its review by three months, NPS said, time it will spend reviewing data on the company's Natpara, a treatment for the rare endocrine disorder hypoparathyroidism. The agency asked NPS to submit a requisite plan for evaluating the drug's safety after approval but, importantly, has not requested any further clinical trials.

The news sent NPS' shares down about 5% in premarket trading on Friday, reflecting investor concerns that the drug will eventually get saddled with sales-limiting restrictions or rejected outright. But the company isn't changing its outlook on Natpara's potential, CEO Francois Nader said.

"We continue to work closely with the FDA to finalize the review of our BLA for Natpara and appreciate the effective collaboration with the agency to date," Nader said in a statement. "We continue to advance our commercial readiness activities and are planning for the launch of Natpara in the second quarter of 2015."

Natpara has had an up-and-down trip through the regulatory process thus far, as FDA staff has taken issue with the biomarkers used to establish its clinical efficacy. Last month, a panel of agency advisers voted 8-5 in favor of its approval, but not without expressing concerns that the drug led to no meaningful improvements in bone mineral density and failed to beat placebo in reducing patients' urinary calcium.

But NPS remains bullish on the drug's future, and the company believes it can launch the orphan treatment on its own, planning to employ the same commercial strategy it used for Gattex, a rare-disease treatment gaining steam on the market.

Natpara replaces human parathyroid hormone 1-84, which is underproduced in patients with hypoparathyroidism. Low levels of the hormone lead to calcium deficiency and difficulty converting vitamin D, spurring complications including paresthesia, muscle pain, bone-density issues and, in acute cases, cardiac arrhythmias, the company said.

Hypoparathyroidism affects nearly 60,000 U.S. patients, according to the National Center for Biotechnology Information, and there are no approved treatments for the root cause of the disease.

- read the statement